Seal for Sealing Shafts

ABSTRACT

In a seal ( 1 ) of shafts ( 7 ) relative to a medium, being received in housing-fixed support rings ( 4, 5 ), it is provided that in an embodiment of the seal with a clamp-in element ( 3 ) and an angled element with a seal lip ( 2 ) arranged via an intermediate part ( 6 ) whereby a contact pressure is applied via a spring ( 10 ). For this it is provided that the spring ( 10 ) is embodied in a receiving groove ( 11 ) as a spring pocket with a free space ( 12 ) for the spring in the pressureless state. A nose ( 13 ) as a retaining element for the inserted spring is arranged on the membrane as an intermediate part ( 6 ) above the spring pocket ( 11 ). The membrane is adjustable upon changing a tilt angle (Ψ) by pressure loading up to reaching a limit pressure for contacting on an allocated housing wall ( 16 ) such as an extended support ring ( 5 ). Thereby an enlarged bottom side contact angle (β) is established in the angled region with the seal lip ( 2 ).

The invention relates to a seal for sealing shafts relative to liquid media, such as propeller shafts, impeller shafts, rudder shafts of ships, consisting of a clamp-in element in allocated housing-fixed support rings as an installation space with an adjoining intermediate part as a membrane and an angled element facing toward the shaft with formation of a seal lip for contact on the shaft, whereby a receiving groove or trough with a spring is arranged in the angled element above the seal lip.

Seals of this type are known in various different embodiments for use for ships. An embodiment according to the generic field is known according to the DE 41 41 999 C2. In this regard it has been found that the adaptability or fitting capability of the seal edge geometry and adjustment of the angled region does not exhibit optimal relationships or conditions under increased pressure loading.

The object of the invention is to enable a good adjustment of the seal and therewith to improve the adjustment of the seal to the prevailing conditions or relationships.

The solution of this object is achieved according to the invention in that the receiving groove is embodied as a spring pocket with a free space for the spring in the pressureless or pressure-free condition.

Hereby it is possible to give the spring a free space for the adjustment of the seal.

In order to enable an improvement of a seal edge geometry under pressure loading, it is suggested that the membrane is adjustable by changing its tilt angle under pressure loading until reaching a limit pressure for contacting on an allocated housing wall, such as an extended support ring, and an enlarged bottom side in contact angle is adjustable in the angled region with the seal lip.

Hereby, relatively good relationships or conditions for forming contact surfaces with advantageous angle relationships at high pressing force are adjustable or settable by a change of the contact angle under pressure loading.

It is further suggested that the free space comprises a depth of 5 to 30% of a spring diameter.

For securing the inserted spring it is suggested that a nose as a retaining element for the inserted spring is arranged on the membrane above the spring pocket.

For forming an advantageous contact surface of the seal it is suggested that the seal lip for contacting on the shaft is formed by a rounded end region of the angled element.

Further it is suggested that at least the region of the seal lip is formed of a more wear resistant elastomer relative to the material of the further part of the seal.

An example embodiment of the invention is schematically illustrated in the drawing. It is shown by:

FIG. 1 a seal as allocated to a shaft at normal pressure, and

FIG. 2 an illustration like FIG. 1 at high pressure.

The illustrated seal 1 is formed of a rubber elastic material, such as an elastomer, whereby at least the region of a formed seal lip 2 is formed of a wear resistant elastomer than the material of the further part of the seal 1.

The seal 1 consists of an upper clamp-in element 3, which is clamped into housing-fixed metallic support rings 4, 5 in a liquid-tight known manner. An intermediate part 6 as a membrane adjoins the clamp-in part 3 of the seal 1, and the intermediate part 6 is embodied at an angle psi as a tilt angle relative to a horizontal (shaft 7).

The intermediate part 6 is connected with an angled region 8 of the seal that faces toward a shaft 7 that is to be sealed, and with its end region it forms the seal lip 2, which lies in contact on the shaft 7 with a bottom side contact angle beta. In this embodiment the seal lip 2 is formed by a rounded end region 9 of the angled region 8 of the seal 1.

For forming or developing a contact pressure of the seal lip 2 on the shaft 7, an allocated spring 10 is provided in addition to the elastic return element of the angled region 8 of the seal 1. In that regard, the spring 10 with a diameter D is received in a receiving groove or trough 11 as a spring pocket and thereby has a formed free space 12 with a free space depth t, which enables a flexible adjustment of the angled region 8 of the seal 1. For securing the spring 10, a nose 13 as a retaining element is arranged on the membrane as intermediate part 6 above the receiving groove 11. The free space depth preferably amounts to 15% of the spring diameter D.

Through this arrangement it is possible to increase or enlarge the bottom side contact angle beta of the seal lip 2 to the shaft 7 under pressure loading, and therewith to correspondingly flexibly adjust it, and to reduce a seal surface so that an advantageous contact width is established.

For limiting the tilt angle psi of the seal 1 upon reaching a provided limit pressure of the medium that is to be sealed, a wall 16 is arranged fixed on the housing. For this, the support ring 5 facing away from the medium to be sealed is extended or lengthened and has a part 14 that is guided or extended radially into the area of the shaft surface, while the support ring allocated to the medium to be sealed ends with a projection or protrusion 15. 

1. Seal for the sealing of shafts relative to liquid media, such as propeller shafts, impeller shafts, rudder shafts of ships, consisting of a clamp-in element in allocated housing-fixed support rings as an installation space with an adjoining intermediate part as a membrane and an angled element facing toward the shaft with formation of a seal lip for contact on the shaft, whereby a receiving groove with a spring is arranged in the angled element above the seal lip, characterized in that the receiving groove is embodied as a spring pocket (11) with a free ii space (12) for the spring (10) in the pressureless condition.
 2. Seal according to claim 1, characterized in that the membrane (6) is adjustable by changing its tilt angle (psi) upon pressure loading up to reaching a limit pressure for contact on an allocated housing wall (16), such as an extended support ring (5), and an enlarged bottom side s contact angle (beta) is settable in the angled region (8) with the seal lip (2).
 3. Seal according to claim 1, characterized in that the free space (12) comprises a depth (t) of 5 to 30% of a spring diameter (D).
 4. Seal according to claim 1, characterized in that a nose (13) as a retaining element for the inserted spring (10) is arranged on the membrane (6) above the spring pocket (11).
 5. Seal according to claim 1, characterized in that the seal lip (2) for contact on the shaft (7) is formed by a rounded end region (9) of the angled element (8).
 6. Seal according to claim 1, characterized in that at least the region of the seal lip (2) is formed of a more wear resistant elastomer relative to the material of the further part of the seal (1). 